Vasopressor requirement during targeted temperature management for out-of-hospital cardiac arrest caused by acute myocardial infarction without cardiogenic shock

OBJECTIVE: We investigated whether patients with out-of-hospital cardiac arrest (OHCA) due to an acute myocardial infarction without cardiogenic shock required higher doses of vasopressors with low targeted temperature management (TTM) after return of spontaneous circulation. METHODS: We included consecutive comatose patients resuscitated from OHCA between January 2011 and December 2013. Patients with return of spontaneous circulation, regional wall motion abnormality on echocardiography, and coronary artery stenosis of ≥70% on percutaneous coronary artery angiography were enrolled. These patients received 36°C TTM or 33°C TTM following approval of TTM by patients’ next-of-kin (36°C and 33°C TTM groups, respectively). The cumulative vasopressor index was compared between groups. RESULTS: During induction phase, dose of vasopressors did not differ between groups. In the maintenance phase, the norepinephrine dose was 0.37±0.57 and 0.26±0.91 µg·kg(-1)·min(-1) in the 33°C and 36°C TTM groups, respectively (P<0.01). During the rewarming phase, the norepinephrine and dopamine doses were 0.49±0.60 and 9.67±9.60 mcg·kg(-1)·min(-1) in the 33°C TTM group and 0.14±0.46 and 3.13±7.19 mcg·kg(-1)·min(-1) in the 36°C TTM group, respectively (P<0.01). The median cumulative vasopressor index was 8 (interquartile range, 3 to 8) and 4 (interquartile range, 0 to 8) in the 33°C and 36°C TTM groups, respectively (P=0.03). CONCLUSION: In this study, patients with OHCA due to acute myocardial infarction without cardiogenic shock had an elevated vasopressor requirement with 33°C TTM compared to 36°C TTM during the maintenance and rewarming phases.